Pneumatic tool



` Nav. 3, 1925( A A. LEVEDAHL PNEUNATIC y TOOL Filed .my 30. i919 2 Sheets-sheet 1 PNsmm'Ic Toor.I

Filed July 30. 1919 2 Sheets-Sheet 2 l wereld Qaeda/Eb l Patented Nov. 3, 1925.

UNITED STATES t liasasi'i AXEL LEVEDAHL, or kunnen, ILLITNoi's, assiettes, 'rof'riaijnrENDENrriviiuivraric Toor. COMPANY, 0F CHICAGO, ILLINOIS, A' 'CORPORATION or DELAWARE.

Appucation ined Jiny v3o, wie; f serial N'o'.- 14,'37.

To all whom t may concern: Y

Be it known that I, AXEL LEVEDAHL, a citizen of the United States, residing at Aurora, in the county of Kane and State of Illinois,I have inventednew and useful Improvements in `Pneumatic Tools, of which the following is va specification.

This inventionrelates to improvements in pneumatic tools and consists of thel matters hereinafter described and more particularly -pointed out in the appended claims. The invention is herein illustrated and described as embodied in a pneumatic tool of the kind known as a sand rammer of the bench type; that is to say, of the type wherein the tool has a relatively short length, so that it may be readily grasped by both hands of an operator and held in a substantially upright position for packing or tamping sand about a pattern in a mold'- ers flask when placed on a bench or other raised support above the floor of the workroom.

The object of my invention is to improve the construction of pneumatic tools used for such purpose, and this object as well as others will be made more apparent as I proceed with my specification.

In the drawings-r Figure 1 is a sidev elevationalv'iew of a sand rammer embodying the features of my invention; y A

Figures 2 and 3y illustrate, collectively, a longitudinal sectionalI view through' the rammer, and on a scale somewhat larger than that shown in Fig; l;

Figures 4and 5 are transverse sectional views taken on lines 4-'4 and `5-`5, respectively, of Fig. 1;

Figures 6 and y locking mechanism and showing 'the pawl thereof in both its locking `andE unlocking positions; n f I Figure 8 is a transverse sectional view taken on line 8-8 of Fig. 6; and

Figure 9 is a top plan, view, with' parts broken away to show a detail'of construction to be hereinafter described:

A sand rammer embodying the features of my invention comprises a hollow barrel 1, as customary in pneumatic tools,l and within which is reciprocated a piston 2 made hollow, as shown in Figs. 2 Vand 3, .for the purpose of reducing the weight of such part. The piston 2 is provided at Vone end- 7 are top plan viewsof the' with :ii-01:11 8 projecting outward from the barrel through the lowerv end th-ereofand having secured thereto a stamper oripeenf 4'. rIihe form of stamp'er 4 shown inthe drawings' is provided witha rectangular stamping face 5 so thatth'e cornersfof a rectangu lar mold or flask maybe reached. Should the flash be circular, a circular stamper may then be applied to the end of the piston rod` 3.. To'l prevent rotation' of` the pistonrod, \vhicl1 would be required when a square `stamp'er 4 is used, I provide thepiston yrod with one or more concave flutes 6 extendingylengthwise thereof and into`v which extend likeyshapedy keys (not shown-) onlthe locking ring 7 of the stuffing box yprovided atthe lower'end of the barrel and through which the piston rod extends'. Theh stuflin'g box structure is the same* 'as that shownl and described vin my co ending application `filed July 30,- 1919, anV having' Serial' Number 314,374.y As in'V such structure, the ring is' provided with a key to engage in a keywayvor groove 8 formed inthe lower vendl of thebarrel to` hol'd the parts from' rotation in the reciprocatingof the piston rodV 3'. The oppositeV or upperend ofthe barrel is enlarged, as at 9', to receive a valve block 10,l in which reciprocates a valve member-'1 1 having differential pressure areas, a feature well` known in the' pneumatic tool' art. Said valvemember 11 serves to control 'the ad# mittance andrexhaustd 'of motive luidto 'and from the opposite ends of the barrel for thepurpose of reciprocatingt-he piston there: in, this feature alsobeing well known this art. The enlarged upper fend 9-of the barrel is left open to permita throttle head 12. to

be attachedthereto and forms a' rearward eX-V tension of the barrel, as shown ink Figs. 1- and 3. Said throttle head 12 isi-'provided with a cylindric extensionY 13v inserted into the open end of the enlargementQl, the eX-V tension 131 having an'external screw' thread toI engage -an internal screw thread in the open end ofsaid enlargement 9, as shown' in Fig. 3. vIn thisv manner, the throttle headvr f 12 is connected with the upper end-ofthe barrel 1.- Said throttle head is provided' with an inlet passage 14 having at itsoutery end screw threads to vpermit the attach-ment thereto of an air supply hose; Formed in the-head 12, to the reariof the extension'13' and crossing' the inlet passage 14 at substantially right-angles thereto, is a circular bore 15 opening at its ends through the head 12 on opposite sidesthereof. Fixed in said bore 15 is a valve housing 16 having ports 17, 18 on opposite sides of a valve seat 19 for permitting the passage'of motive fluid through the valve housing when the valve member 2O is in open position, as shown in Fig. 3.

vSaid valve member 2O is in the form ot a upper end extending beyond the like endy of the .housing 16, and over both of which is placed a dust cap 24, Ycup-shaped and having an inwardly extending annular wall 25 extending downward over the upper end of the valve Vhousing 16, as shown in Fig. 3.

' For opening the ball valve 20, I provide a hand lever'26 located Von the outside of the tool; and having at its rear end laterally spaced ears 27 engaging over the sides of the throttle head 12 and secured thereto by a pivot:pin'-28. Thelever 26 extends along the barrel 1 toward its lower end and to a point beyond the'enlargement 9, as shown in the drawings, and is curved transversely to conform to the curvature of the barrel 1 and its enlargement 9 so that when the lever is in position holding*` the valve 20 'fully opened, as shown in Fig. 3, the lever will lie against the barrel and have no part thereof projecting beyondtlie same to strike exterior objects inthe handling of the tool during the operation thereof. The Aforward end 29 of the lever'is otfset toward the barrel so that such end Vwill'engage over the barrel beyond the shoulder V30 formed at the junction of thebarrel 1 with its enlargement 9. The barrel 1 is provided Abetween its ends and adjacent thevenlargment 9, but beyond thej'forward end of the lever 2V, with an an! nular, outwardly projecting vrib B1, so positioned as'to prevent thejhandofthe oper` atorr grasping thevbarrel andholding the leverin open Aposition from sliding down the' barrel and olf the-end ot theplever. By the provision ofthe'dust cap24--and havingl the same slide overy the adjacent-end of the, valve housing 16, sand, dirt, and dust areprevented froinentering the' valve housing' 16 at such point, and "thus the valve stein is prevented from being injured or damaged and from'an accumulation of sand and dirt between such parts. The lever 26 extends over the dust cap 24 and-is provided with an outwardly curved portion 32 to conform to the curvature at the top of the dust cap, and thus' provides a :suitable 'connection between the valve stem 23 andthe lever26, so that the swinging movement of the lever converted into a straight reciprocating action between the dust cap and the valve stem, thereby allowing the valve to be arranged at right-angles to the passage ot the air to the block 10, and also eliminates wear on the parts. Moreover, the construction described permits the use of a one-pieced throttle lever and conforms to the shape ot the handle ot' the tool and makes an easy grip for the hand of. the operator, as is" apparent.

The exhausts from the various ports and passages of the tool empty into an annular space 33 about the valve fblock 10, as shown in Fig. 3, and said space communicates at its rear end with tive ports 34:,A as clearly shown in Fig. The port'e is made larger than anyA one of the ports and communicates with the upper end of the bore 15 around the reduced end of the valve housing `16r at the dust'cap 24- and reaches the atmosphere through 'a cluster ot ports 36, 36 in the portion 30 of the 'throttle lever 26 in contact withthe'dust cap, as shown in Figs. 3 and 9. The sets of ports on opposite sides ot the port't coninuinicat'e with passages 37 formed inthe throttle head 12 on opposite sides of the bore l5, in which the valve housing 16 located. Said passages 37 open outward through the throttle head beneath the throttle lever 26 and reach the atmosphere through ports 38, 38 in said throttle lever yandY on opposite sides of the cluster of ports 36, as shown in Fig. 9. c

To lock the throttle head l2 on the barrel 1 and prevent the lsaine fromV being unscrewed by the jarring of the tool while in use or otherwise, the upperend "of the-bar? relis provided'with-a plurality of ratchet teeth 39 covering the lentire end offthebarrel, as shown in Fig. 5. In the throttle `head is alocking pawl /10 slidably mounted in a d'ovetailed slot `L1:1 closed at its inner end and opening at its outer end through the adjacent end of thef'thij'ettle head 12,.,so that they pawl may project beyondthe'openend of the slot and engage the ratchet teeth 3f) on the barrel l, as shown in Figs. 1 and 6. The' pawl 40 Aisshaped to tit and slide endwise in the sl'ot 451, so that the pawl will not drop out'of the slo't'throughthe"open upper side thereof. For projecting the pawl 4t() forward against the .ratchet teeth 39,1131'0- vide a spiralspring`42-its innerend entern ing a recess 18fbeyond the inner Vend -otthe slotgl and opening into -the same, andthe other end oft the springextendi'ng'into an aligned recess 111 in the pawl 40. rllhe spring` serves to force the pawl-toward the barrell and permitsy the pawl to ratchet over the teeth 39 as 'the throttle lhead '12 is' screwed on the end of the barrehthe facelof the teeth' 39 and those te on -the pawlbeing rompiementary but arranged to permit the pa wl ,to

llO

ratchet over the same i'n thevs'creu'ing up of the head l2 on the barrel. Said teeth, however, are" formed to prevent aA reverse movement of the parts, and therefore when the pawl engages the teeth 39, relative rotation oiv the head l2fand the `barrel l inca direction-to unseren' `'such parts .vill be prevented. In order to permit the head l2 ltobc un-r screived from the barrel, when that is desired, a suitable pointed implement or hand tool (not shown) is inserted into a V.notch 45" in one side ofthe pawl, whereupon the pawl is retracted until said notch is brought into-register ivith a notch 46 in the head l2 adjacentthe rear end of the.V slot 4l. Then the parts occupy such position, thepaivl is disengaged from'the teethi-SQ, and to prevent the spring'42 from projectingthe paivl forward, apiece of metal 4i? is inserted into the registering notches l45, 46 to make the pawl ineffective'ivl'iile unscrewing the head l2 romthe end of the barrel.V The pawl 40 has aV vplurality of teeth, as shown, and the headl l2' atone sideof the slot 4l is provided With a lug 48, which extends into a groove 49 in one sidefof the pawl and in the path ci a shoulderr 50 at the rear end of said groove to prevent the paivl from slipping out of the slotV 41 When the head 12 is dissembled from the barrel.

In use, the operator grasps the barrel l with both hands, one above the other, and raises the tool into positionto pack or stamp sand about a pattern ina mold or flask when on a bench, or elevatedfsupport. The length and weight oi the tool`- are such that this may be readily and easily done. IVhen' the tool is raised to the position desired with its stamper 4 on the sand in the {iaslr or mold, the operator with his upper hand grasps the throttle lever 26 and draws 1t into contact with the barrel, thereupon opening the ball valve 20 and permitting live air to be supplied to the Working parts of the tool. The transverse curvature of the lever 26 being the same as the barrel, permits the lever to lie along and in Contact with the barrel so that the hand of theV operator grasping the lever may be also used to grasp the barrel at the lever in a natural and easy manner. In the vibration of the tool, the upper hand of the operator may slide down the barrel, but it is prevented from sliding olf the free end of the ylever 26 by contact with the annular rib 3l. This forms a support for the hand of the operator, and he need only use such force in grasping the tool as is necessary to hold the valve 2,0 open against the tension of the spring 21 and maintain the tool in a substantially upright position required during the operation thereof. When it is desired to stop the operation of the tool, the operator releases the lever 26 and, by the action of the spring 2l,.the valve 2O is closed, With the lever remaining in a ypositiongto be grasped readily again for' supplying motive fluid to the tool lor operating it. i

'The constructidn described and shown possesses many advantages, which are as l'ollovvs: The throttle valve mechanism is contained in a compact form-'1n a throttle the upper end of the barrel l1 and'Will not project to any great extent beyond thetlend of vthe barrelv to increase 'materially' the support. The throttle *lever 26 lies along and in Contact With 'the'v barrel when holding thevalve' in open position and' therefore 'may be readily grasped by the hand ofthe operatorjand permitvhi'm to have Valllhis iingersaround they barrel ofthe tool 'at the same time,- and thus avoid vthe useolf any oneof his fingers of that hand to extend beyond the barrel for grasping the 'throttle lever. Moreoventhe throttle vlever isin one piece andtherefore/has no parts projecting beyond the barrel for holding the valve Vin open position. The vdust cap 24 permits the swingingmovement of the throttle; lever to be converted into astraight reciprocating motion with the valve' stem', andi prevents sand, dirt, and dust from entering between' the valve housing or bushingl6 and the valve stem, thus saving Wear on suchparts. The locking device* between thejthrottle head and the barrel is 'positive'andfvvill lock the head against accidental movement or being jar'red loose from strains and shocks to which the parts are likely to be subjected in the use of the tool. Other and further advantages of my invention Will be apparent to those skilled in the art to which it relates.

While I have shown and described in detail a sand rammer constructed in accordance With my invention, yet itis of course to be understood that the several details of construction and arrangement of parts shown may be variously changed and modied Without departing from Vthe Spirit and scope of my invention.

I claim as my invention:

l. In a pneumatic tool, the combination a barrel, a throttle head securedto the rear end thereof and having a live air passage and an exhaust po-rt, a self closing throttle valve for said passage, and a valve opening lever pivoted on said head at the rear of said valve and extending over the valve to- Ward the forward end of said barrel, said lever having engagement `between its ends with said valve for opening said valve upon the movement of said lever toward said barrel, said lever being c urved transversely to conform to the curvature of said barrel and head, Which mayV be readily connectedvvith llO provided in its portion extending over said valve with an exhaust port in communication with the exhaust port in said head.

2. In a pneumatic tool, the combination of a barrel, a throttle head secured to the rear end of said barrel and having a live air passage and an exhaust port,said throttle head having a bore extending across said passage and communicating with said exhaust port, a bushing in said bore and having a Valve seat communicating on opposite sides with said passage, a valve memberin said'bushing and having a stem extending through one end thereof, and a valve opening lever pivoted to said head at the rear side of said valve and extending over the valve toward vtheA forward end of said barrel, said lever having engagement between its ends with said valve stemfor opening said valvev upon the movementvof saidlever toward said barrel, said lever being provided in its portion extending over said valve with an exhaust port in communication with said bore. Y

3. In a pneumatic tool, the combination of a barrel, a throttle head secured to the rear end of said 4barrel and having a live air passage and a bore extending across said passage, va bushing `in said bore and having a valve seat communicating o-n opposite sides with said passage, a valve member in said bushing and having a stem extending through the open end thereof, a dust cap applied over said stem and adjacent end of said bushing and having sliding engagementtherewith, a valve opening lever pivoted to said head at the rear side of said valve and extending over the valve toward the forward end of said barrel, said lever having engagement between its ends with said dust cap for opening said valve upon the movement of said lever toward said barrel, and a spring for normally holding said valve member against its seat and said dust cap against said lever.

4. In a pneumatic tool, the combination of a barrel, a throttle head secured to the rear end of saidbarrel and having a live air passage and a plurality of exhaust ports, said head having a bore extending across said passage and communicating with one of said exhaust ports, a bushing in said bore and having a valve seat communicating on opposite sides with said passage, a valve member in said bushing and having a stem extending` through one end thereof, a valve opening lever pivoted to said head at the rear side of said valve and extending over the valve toward the forward end of said barrel, said lever having engagement between its ends with said stem for opening said valve upon the movement of said lever toward said barrel, said lever being pro-- vided with two sets of exhaust ports, one set communicating with the exhaust port opening into said bore and the other set comf municating with the other of said exhaust ports in said throttle head.

In testimony that I claim the foregoing as my invention, I ax my signature, this 26 day of July, A. D. 1919.

AXEL LEVEDAHL. 

